Computer systems having at least two power supply units for producing an operating voltage for at least one power-consuming component are widely known. In the field of high-performance or high-availability servers in particular, power supply units are frequently designed in a redundant manner, with the result that it is still possible to operate the computer system even when one or possibly more power supply units fail. In addition, further computer systems having redundant power supply units are known, for example, from the field of telecommunications and control and monitoring systems.
The number and performance of the redundant power supply units may be different depending on the power consumption of the power-consuming component. In particular, more than one high-performance redundant power supply unit is often provided in this case in so-called “high-availability” systems.
The known computer systems have two fundamental disadvantages. On the one hand, each power supply unit must be designed to be more powerful than is necessary for normal operation. Only in this manner can it be ensured that the remaining power supply units are not loaded beyond their maximum output power even when a power supply unit fails. This leads, inter alia, to increased costs of the computer system since particularly powerful power supply units are more expensive than medium-performance or lower-performance power supply units.
In addition, all power supply units in the known computer systems are generally active and contribute to supplying the power-consuming component. Consequently, each power supply unit is operated well below its maximum rated output power during normal operation. However, this reduces the energy efficiency in the case of switched-mode power supplies and similar converter circuits for producing an output-side operating voltage from at least one input-side supply voltage. This is because it is advantageous to operate a power supply unit in the vicinity of its maximum output power to achieve the highest possible efficiency.
It could therefore be helpful to describe a computer system of the type mentioned above and a method for controlling the latter, which computer system solves or diminishes the above-mentioned problems. In this case, the failure safety of the computer system as a whole and, in particular, the power supply for the power-supplying component should be ensured even when at least one power supply unit fails. In addition, the computer system should have the simplest possible construction and be able to be produced in a cost-effective manner.